Three-Dimensional Graphene-Wrapped CoSe2 Nanowires for High-Performance Asymmetric Supercapacitors

Herein, a three-dimensional graphene (3DG)-coated porousnanowirearchitecture was developed, which exhibited favorable multiscale andmultidimensional porous nanostructures, resulting in an airgel (3DG/CoSe(2)NWs) with abundant ion transport channels, high specific surfacearea, and excellent electrical conductivity. This airgel can be useddirectly as a flexible binder-free electrode with a high specificcapacity of 1272 F g(-1) at 1 A g(-1) and an excellent rate capability of 1156 F g(-1) when the current density was increased to 10 A g(-1). The prepared asymmetric supercapacitor (3DG/CoSe(2)NWs//AC)exhibited excellent cycle stability with a coulombic efficiency of96.19% at 5 A g(-1) after 10,000 cycles. The performanceof the flexible asymmetric supercapacitor (ASC) device under differentbending angles was evaluated, and the discharge stability was confirmed,which indicated its potential in practical applications. Furthermore,two 3DG/CoSe(2)NWs//AC ASCs (1 cm x 3 cm) connectedin series were able to light up an LED lamp, highlighting the promisingprospect of the device.

Automated summary

A three-dimensional graphene (3DG)-coated porous nanowire architecture was developed, which resulted in an airgel (3DG/CoSe(2)NWs) with abundant ion transport channels, high specific surface area, and excellent electrical conductivity. The airgel demonstrated a high specific capacity and rate capability, making it suitable for use as a flexible binder-free electrode. The asymmetric supercapacitor (3DG/CoSe(2)NWs//AC) exhibited excellent cycle stability and the flexible ASC device showed discharge stability, indicating its potential in practical applications.